Sukkah, Daf Yod Het, Part Five
Introduction
Today’s section deals with a place in front of a Roman style building called the "exedra" (there is an entry for this on Wikipedia, you can look it up). Rashi explains that in courtyards that were surrounded by the houses, there was a covered open area called the exedra. Our sugya refers to a sukkah built in the open space not covered by the roof of the exedra. The skhakh is resting on the exedra roof. This was also referred to in the mishnah that began daf yod zayin.
אתמר, סיכך על גבי אכסדרה שיש לה פצימין – כשרה. שאין לה פצימין, אביי אמר: כשרה, ורבא אמר פסולה.
It was stated: If one placed skhakh over an exedra which has pillars, it is valid;
If it has no pillars: Abaye declares it valid and Rava declares it invalid.
Rashi explains that the sukkah built on top of the exedra is too far from the walls of the house for those walls to count. As we learned in the mishnah, if the walls are more than four cubits from the skhakh, the walls cannot count as part of the sukkah. However, if there are pillars that hold up the roof of the exedra and there are less than three handbreadths between each pillar, the sukkah is valid. In this case, the pillars can count as the wall and the sukkah is valid.
However, there is a debate between Abaye and Rava if there are no pillars. Abaye says it is still valid, whereas Rava declares it invalid. Each amora will now explain their position.
אביי אמר כשרה אמרינן: פי תקרה יורד וסותם.
רבא אמר פסולה: לא אמרינן פי תקרה יורד וסותם.
Abaye declares it valid [since] we say that the edge of the roof [of the exedra is regarded as though it] descends and fills up [the space].
While Raba says it is invalid, since we do not say that the edge of the roof descends and fills up [the space].
Abaye uses a legal fiction to pretend that there are walls for this sukkah. The roof of the exedra, upon which the skhakh rests, is looked at if its edges goes down to the ground and fill up the space needed for a wall.
Rava does not invoke this legal fiction.
אמר ליה רבא לאביי: לדידך דאמרת פי תקרה יורד וסותם – אפילו הפחית דופן אמצעי! –
Rava said to Abaye: according to you who say that the edge of the roof [is regarded as though it] descends and fills in [the space, is a sukkah valid] even if the middle wall is missing?
Rava raises a rhetorical difficulty on Abaye. If there is a regular sukkah with three walls and the middle wall falls down, we could look at the edges of the existent two walls as if they fictiously go down to the ground and create a third wall. This would be absurd for it would in essence validate all two walled sukkot.
אמר ליה: מודינא לך בההיא, דהוה ליה כמבוי המפולש.
He answered him, In that case I agree with you [that the Sukkah is invalid] since it would be like an alley-way that is open on two opposite sides.
Abaye agrees that this sukkah is invalid because with two parallel walls it is like an alley-way. There is no way to consider the third wall as fictitiously existing.